1. Field of the Invention
The present invention relates to the alkylation of paraffinic hydrocarbon feed stocks. The present invention provides both an improvement in the operating conditions and the feed stock for acid paraffin alkylations.
2. Related Information
The common objective of most alkylation processes is to bring isoalkanes (or aromatics) and light olefins into intimate contact with an acid catalyst to produce an alkylation product. In the petroleum refining industry, acid catalyzed alkylation of aliphatic hydrocarbons with olefinic hydrocarbons is a well known process. Alkylation is the reaction of a paraffin, usually isoparaffins, with an olefin in the presence of a strong acid which produces paraffins, e.g., of higher octane number than the starting materials and which boil in range of gasolines. In petroleum refining the reaction is generally the reaction of a C3 to C5 olefin with isobutane.
In refining alkylations, hydrofluoric or sulfuric acid catalysts are most widely used under low temperature conditions. Low temperature or cold acid processes are favored because side reactions are minimized. In the traditional process the reaction is carried out in a reactor where the hydrocarbon reactants are dispersed into a continuous acid phase.
Although this process has not been environmentally friendly and is hazardous to operate, no other process has been as efficient and it continues to be the major method of alkylation for octane enhancement throughout the world. In view of the fact that the cold acid process will continue to be the process of choice, various proposals have been made to improve and enhance the reaction and, to some extent, moderate the undesirable effects.
U.S. Pat. No. 5,220,095 disclosed the use of particulate polar contact material and fluorinated sulfuric acid for the alkylation. U.S. Pat. Nos. 5,420,093 and 5,444,175 sought to combine the particulate contact material and the catalyst by impregnating a mineral or organic support particulate with sulfuric acid.
Various static systems have been proposed for contacting liquid/liquid reactants, for example, U.S. Pat. Nos. 3,496,996; 3,839,487; 2,091,917; and 2,472,578. However, the most widely used method of mixing catalyst and reactants is the use of various arrangements of blades, paddles, impellers and the like that vigorously agitate and blend the components together, for example, see U.S. Pat. Nos. 3,759,318; 4,075,258; and 5,785,933.
The present application presents a significant advance in the technology relating to alkylation and, in particular, to petroleum refining paraffin alkylation by providing both an effective method for the alkylation, novel olefinic feed and an apparatus for obtaining a high degree of contact between the liquid catalyst and the fluid reactants without mechanical agitation thereby eliminating shaft seals, reducing costs and improving acid product separation.